Read lines from a text file and print those lines based on condition using perl

 use strict;

use warnings;

#disabling output buffering

$|=1;

sub main{

#my @files=('./a.txt','./b.txt','./c.txt',);

my $file='./a.txt';

open(INPUT,$file) or die("Input file $file not found.\n");

while(my $line=<INPUT>)

{

if($line=~/abc/)

{

print $line;

}

}

close(INPUT);

}

main();